    /**
     * The TreeStore is a store implementation that is backed by by an {@link Ext.data.Tree}.
     * It provides convenience methods for loading nodes, as well as the ability to use
     * the hierarchical tree structure combined with a store. This class is generally used
     * in conjunction with {@link Ext.tree.Panel}. This class also relays many events from
     * the Tree for convenience.
     *
     * # Using Models
     *
     * If no Model is specified, an implicit model will be created that implements {@link Ext.data.NodeInterface}.
     * The standard Tree fields will also be copied onto the Model for maintaining their state. These fields are listed
     * in the {@link Ext.data.NodeInterface} documentation.
     *
     * # Reading Nested Data
     *
     * For the tree to read nested data, the {@link Ext.data.reader.Reader} must be configured with a root property,
     * so the reader can find nested data for each node (if a root is not specified, it will default to
     * 'children'). This will tell the tree to look for any nested tree nodes by the same keyword, i.e., 'children'.
     * If a root is specified in the config make sure that any nested nodes with children have the same name.
     * Note that setting {@link #defaultRootProperty} accomplishes the same thing.
     */
    Ext.define('Ext.data.TreeStore', {
        extend: 'Ext.data.AbstractStore',
        alias: 'store.tree',
        requires: [
            'Ext.util.Sorter',
            'Ext.data.Tree',
            'Ext.data.NodeInterface'
        ],

        /**
         * @cfg {Ext.data.Model/Ext.data.NodeInterface/Object} root
         * The root node for this store. For example:
         *
         *     root: {
         *         expanded: true,
         *         text: "My Root",
         *         children: [
         *             { text: "Child 1", leaf: true },
         *             { text: "Child 2", expanded: true, children: [
         *                 { text: "GrandChild", leaf: true }
         *             ] }
         *         ]
         *     }
         *
         * Setting the `root` config option is the same as calling {@link #setRootNode}.
         */

        /**
         * @cfg {Boolean} [clearOnLoad=true]
         * Remove previously existing child nodes before loading.
         */
        clearOnLoad : true,

        /**
         * @cfg {Boolean} [clearRemovedOnLoad=true]
         * If `true`, when a node is reloaded, any records in the {@link #removed} record collection that were previously descendants of the node being reloaded will be cleared from the {@link #removed} collection.
         * Only applicable if {@link #clearOnLoad} is `true`.
         */
        clearRemovedOnLoad: true,

        /**
         * @cfg {String} [nodeParam="node"]
         * The name of the parameter sent to the server which contains the identifier of the node.
         */
        nodeParam: 'node',

        /**
         * @cfg {String} [defaultRootId="root"]
         * The default root id.
         */
        defaultRootId: 'root',

        /**
         * @cfg {String} [defaultRootProperty="children"]
         * The root property to specify on the reader if one is not explicitly defined.
         */
        defaultRootProperty: 'children',

        /**
         * @cfg {Boolean} [folderSort=false]
         * Set to true to automatically prepend a leaf sorter.
         */
        folderSort: false,

        constructor: function(config) {
            var me = this,
                root,
                fields;

            config = Ext.apply({}, config);

            /**
             * If we have no fields declare for the store, add some defaults.
             * These will be ignored if a model is explicitly specified.
             */
            fields = config.fields || me.fields;
            if (!fields) {
                config.fields = [
                    {name: 'text', type: 'string'}
                ];
            }

            me.callParent([config]);

            // We create our data tree.
            me.tree = new Ext.data.Tree();

            me.relayEvents(me.tree, [
                /**
                 * @event append
                 * @inheritdoc Ext.data.Tree#append
                 */
                "append",

                /**
                 * @event remove
                 * @inheritdoc Ext.data.Tree#remove
                 */
                "remove",

                /**
                 * @event move
                 * @inheritdoc Ext.data.Tree#move
                 */
                "move",

                /**
                 * @event insert
                 * @inheritdoc Ext.data.Tree#insert
                 */
                "insert",

                /**
                 * @event beforeappend
                 * @inheritdoc Ext.data.Tree#beforeappend
                 */
                "beforeappend",

                /**
                 * @event beforeremove
                 * @inheritdoc Ext.data.Tree#beforeremove
                 */
                "beforeremove",

                /**
                 * @event beforemove
                 * @inheritdoc Ext.data.Tree#beforemove
                 */
                "beforemove",

                /**
                 * @event beforeinsert
                 * @inheritdoc Ext.data.Tree#beforeinsert
                 */
                "beforeinsert",

                /**
                 * @event expand
                 * @inheritdoc Ext.data.Tree#expand
                 */
                "expand",

                /**
                 * @event collapse
                 * @inheritdoc Ext.data.Tree#collapse
                 */
                "collapse",

                /**
                 * @event beforeexpand
                 * @inheritdoc Ext.data.Tree#beforeexpand
                 */
                "beforeexpand",

                /**
                 * @event beforecollapse
                 * @inheritdoc Ext.data.Tree#beforecollapse
                 */
                "beforecollapse",

                /**
                 * @event sort
                 * @inheritdoc Ext.data.Tree#sort
                 */
                "sort",

                /**
                 * @event rootchange
                 * @inheritdoc Ext.data.Tree#rootchange
                 */
                "rootchange"
            ]);

            me.tree.on({
                scope: me,
                remove: me.onNodeRemove,
                // this event must follow the relay to beforeitemexpand to allow users to
                // cancel the expand:
                beforeexpand: me.onBeforeNodeExpand,
                beforecollapse: me.onBeforeNodeCollapse,
                append: me.onNodeAdded,
                insert: me.onNodeAdded,
                sort: me.onNodeSort
            });

            me.onBeforeSort();

            root = me.root;
            if (root) {
                delete me.root;
                me.setRootNode(root);
            }

            //<deprecated since=0.99>
            if (Ext.isDefined(me.nodeParameter)) {
                if (Ext.isDefined(Ext.global.console)) {
                    Ext.global.console.warn('Ext.data.TreeStore: nodeParameter has been deprecated. Please use nodeParam instead.');
                }
                me.nodeParam = me.nodeParameter;
                delete me.nodeParameter;
            }
            //</deprecated>
        },

        // inherit docs
        setProxy: function(proxy) {
            var reader,
                needsRoot;

            if (proxy instanceof Ext.data.proxy.Proxy) {
                // proxy instance, check if a root was set
                needsRoot = Ext.isEmpty(proxy.getReader().root);
            } else if (Ext.isString(proxy)) {
                // string type, means a reader can't be set
                needsRoot = true;
            } else {
                // object, check if a reader and a root were specified.
                reader = proxy.reader;
                needsRoot = !(reader && !Ext.isEmpty(reader.root));
            }
            proxy = this.callParent(arguments);
            if (needsRoot) {
                reader = proxy.getReader();
                reader.root = this.defaultRootProperty;
                // force rebuild
                reader.buildExtractors(true);
            }
        },

        // inherit docs
        onBeforeSort: function() {
            if (this.folderSort) {
                this.sort({
                    property: 'leaf',
                    direction: 'ASC'
                }, 'prepend', false);
            }
        },

        /**
         * Called before a node is expanded.
         * @private
         * @param {Ext.data.NodeInterface} node The node being expanded.
         * @param {Function} callback The function to run after the expand finishes
         * @param {Object} scope The scope in which to run the callback function
         */
        onBeforeNodeExpand: function(node, callback, scope) {
            if (node.isLoaded()) {
                Ext.callback(callback, scope || node, [node.childNodes]);
            }
            else if (node.isLoading()) {
                this.on('load', function() {
                    Ext.callback(callback, scope || node, [node.childNodes]);
                }, this, {single: true});
            }
            else {
                this.read({
                    node: node,
                    callback: function() {
                        Ext.callback(callback, scope || node, [node.childNodes]);
                    }
                });
            }
        },

        //inherit docs
        getNewRecords: function() {
            return Ext.Array.filter(this.tree.flatten(), this.filterNew);
        },

        //inherit docs
        getUpdatedRecords: function() {
            return Ext.Array.filter(this.tree.flatten(), this.filterUpdated);
        },

        /**
         * Called before a node is collapsed.
         * @private
         * @param {Ext.data.NodeInterface} node The node being collapsed.
         * @param {Function} callback The function to run after the collapse finishes
         * @param {Object} scope The scope in which to run the callback function
         */
        onBeforeNodeCollapse: function(node, callback, scope) {
            callback.call(scope || node, node.childNodes);
        },

        onNodeRemove: function(parent, node, isMove) {
            var me = this,
                removed = me.removed;

            if (!node.isReplace && Ext.Array.indexOf(removed, node) == -1) {
                removed.push(node);
            }

            if (me.autoSync && !me.autoSyncSuspended && !isMove) {
                me.sync();
            }
        },

        onNodeAdded: function(parent, node) {
            var me = this,
                proxy = me.getProxy(),
                reader = proxy.getReader(),
                data = node.raw || node[node.persistenceProperty],
                dataRoot;

            Ext.Array.remove(me.removed, node);

            if (!node.isLeaf()) {
                dataRoot = reader.getRoot(data);
                if (dataRoot) {
                    me.fillNode(node, reader.extractData(dataRoot));
                    delete data[reader.root];
                }
            }

            if (me.autoSync && !me.autoSyncSuspended && (node.phantom || node.dirty)) {
                me.sync();
            }
        },

        onNodeSort: function() {
            if(this.autoSync && !this.autoSyncSuspended) {
                this.sync();
            }
        },

        /**
         * Sets the root node for this store.  See also the {@link #root} config option.
         * @param {Ext.data.Model/Ext.data.NodeInterface/Object} root
         * @return {Ext.data.NodeInterface} The new root
         */
        setRootNode: function(root, /* private */ preventLoad) {
            var me = this;

            root = root || {};
            if (!root.isModel) {
                // create a default rootNode and create internal data struct.
                Ext.applyIf(root, {
                    id: me.defaultRootId,
                    text: 'Root',
                    allowDrag: false
                });
                Ext.data.NodeInterface.decorate(me.model);
                root = Ext.ModelManager.create(root, me.model);
            } else if (root.isModel && !root.isNode) {
                Ext.data.NodeInterface.decorate(me.model);
            }

            // Because we have decorated the model with new fields,
            // we need to build new extactor functions on the reader.
            me.getProxy().getReader().buildExtractors(true);

            // When we add the root to the tree, it will automaticaly get the NodeInterface
            me.tree.setRootNode(root);

            // If the user has set expanded: true on the root, we want to call the expand function
            if (preventLoad !== true && !root.isLoaded() && (me.autoLoad === true || root.isExpanded())) {
                me.load({
                    node: root
                });
            }

            return root;
        },

        /**
         * Returns the root node for this tree.
         * @return {Ext.data.NodeInterface}
         */
        getRootNode: function() {
            return this.tree.getRootNode();
        },

        /**
         * Returns the record node by id
         * @return {Ext.data.NodeInterface}
         */
        getNodeById: function(id) {
            return this.tree.getNodeById(id);
        },

        /**
         * Loads the Store using its configured {@link #proxy}.
         * @param {Object} options (Optional) config object. This is passed into the {@link Ext.data.Operation Operation}
         * object that is created and then sent to the proxy's {@link Ext.data.proxy.Proxy#read} function.
         * The options can also contain a node, which indicates which node is to be loaded. If not specified, it will
         * default to the root node.
         */
        load: function(options) {
            options = options || {};
            options.params = options.params || {};

            var me = this,
                node = options.node || me.tree.getRootNode(),
                root;

            // If there is not a node it means the user hasnt defined a rootnode yet. In this case lets just
            // create one for them.
            if (!node) {
                node = me.setRootNode({
                    expanded: true
                }, true);
            }

            if (me.clearOnLoad) {
                if(me.clearRemovedOnLoad) {
                    // clear from the removed array any nodes that were descendants of the node being reloaded so that they do not get saved on next sync.
                    me.clearRemoved(node);
                }
                // temporarily remove the onNodeRemove event listener so that when removeAll is called, the removed nodes do not get added to the removed array
                me.tree.un('remove', me.onNodeRemove, me);
                // remove all the nodes
                node.removeAll(false);
                // reattach the onNodeRemove listener
                me.tree.on('remove', me.onNodeRemove, me);
            }

            Ext.applyIf(options, {
                node: node
            });
            options.params[me.nodeParam] = node ? node.getId() : 'root';

            if (node) {
                node.set('loading', true);
            }

            return me.callParent([options]);
        },

        /**
         * Removes all records that used to be descendants of the passed node from the removed array
         * @private
         * @param {Ext.data.NodeInterface} node
         */
        clearRemoved: function(node) {
            var me = this,
                removed = me.removed,
                id = node.getId(),
                removedLength = removed.length,
                i = removedLength,
                recordsToClear = {},
                newRemoved = [],
                removedHash = {},
                removedNode,
                targetNode,
                targetId;

            if(node === me.getRootNode()) {
                // if the passed node is the root node, just reset the removed array
                me.removed = [];
                return;
            }

            // add removed records to a hash so they can be easily retrieved by id later
            for(; i--;) {
                removedNode = removed[i];
                removedHash[removedNode.getId()] = removedNode;
            }

            for(i = removedLength; i--;) {
                removedNode = removed[i];
                targetNode = removedNode;
                while(targetNode && targetNode.getId() !== id) {
                    // walk up the parent hierarchy until we find the passed node or until we get to the root node
                    targetId = targetNode.get('parentId');
                    targetNode = targetNode.parentNode || me.getNodeById(targetId) || removedHash[targetId];
                }
                if(targetNode) {
                    // removed node was previously a descendant of the passed node - add it to the records to clear from "removed" later
                    recordsToClear[removedNode.getId()] = removedNode;
                }
            }

            // create a new removed array containing only the records that are not in recordsToClear
            for(i = 0; i < removedLength; i++) {
                removedNode = removed[i];
                if(!recordsToClear[removedNode.getId()]) {
                    newRemoved.push(removedNode);
                }
            }

            me.removed = newRemoved;
        },

        /**
         * Fills a node with a series of child records.
         * @private
         * @param {Ext.data.NodeInterface} node The node to fill
         * @param {Ext.data.Model[]} newNodes The records to add
         */
        fillNode: function(node, newNodes) {
            var me = this,
                ln = newNodes ? newNodes.length : 0,
                sorters = me.sorters,
                i, sortCollection,
                needsIndexSort = false,
                performLocalSort = ln && me.sortOnLoad && !me.remoteSort && sorters && sorters.items && sorters.items.length,
                node1, node2;

            // See if there are any differing index values in the new nodes. If not, then we do not have to sortByIndex
            for (i = 1; i < ln; i++) {
                node1 = newNodes[i];
                node2 = newNodes[i - 1];
                needsIndexSort = node1[node1.persistenceProperty].index != node2[node2.persistenceProperty].index;
                if (needsIndexSort) {
                    break;
                }
            }

            // If there is a set of local sorters defined.
            if (performLocalSort) {
                // If sorting by index is needed, sort by index first
                if (needsIndexSort) {
                    me.sorters.insert(0, me.indexSorter);
                }
                sortCollection = new Ext.util.MixedCollection();
                sortCollection.addAll(newNodes);
                sortCollection.sort(me.sorters.items);
                newNodes = sortCollection.items;

                // Remove the index sorter
                me.sorters.remove(me.indexSorter);
            } else if (needsIndexSort) {
                Ext.Array.sort(newNodes, me.sortByIndex);
            }

            node.set('loaded', true);
            for (i = 0; i < ln; i++) {
                node.appendChild(newNodes[i], undefined, true);
            }

            return newNodes;
        },

        /**
         * Sorter function for sorting records in index order
         * @private
         * @param {Ext.data.NodeInterface} node1
         * @param {Ext.data.NodeInterface} node2
         * @return {Number}
         */
        sortByIndex: function(node1, node2) {
            return node1[node1.persistenceProperty].index - node2[node2.persistenceProperty].index;
        },

        // inherit docs
        onProxyLoad: function(operation) {
            var me = this,
                successful = operation.wasSuccessful(),
                records = operation.getRecords(),
                node = operation.node,
                filtered,
                childNodes,
                len,
                i;

            me.loading = false;
            node.set('loading', false);
            if (successful) {
                if (!me.clearOnLoad) {
                    records = me.cleanRecords(node, records);
                }
                records = me.fillNode(node, records);
            }
            // The load event has an extra node parameter
            // (differing from the load event described in AbstractStore)
            /**
             * @event load
             * Fires whenever the store reads data from a remote data source.
             * @param {Ext.data.TreeStore} this
             * @param {Ext.data.NodeInterface} node The node that was loaded.
             * @param {Ext.data.Model[]} records An array of records.
             * @param {Boolean} successful True if the operation was successful.
             */
            // deprecate read?
            me.fireEvent('read', me, operation.node, records, successful);
            me.fireEvent('load', me, operation.node, records, successful);
            //this is a callback that would have been passed to the 'read' function and is optional
            Ext.callback(operation.callback, operation.scope || me, [records, operation, successful]);
        },

        cleanRecords: function(node, records){
            var nodeHash = {},
                childNodes = node.childNodes,
                i = 0,
                len  = childNodes.length,
                out = [],
                rec;

            // build a hash of all the childNodes under the current node for performance
            for (; i < len; ++i) {
                nodeHash[childNodes[i].getId()] = true;
            }

            for (i = 0, len = records.length; i < len; ++i) {
                rec = records[i];
                if (!nodeHash[rec.getId()]) {
                    out.push(rec);
                }
            }

            return out;
        },

        // inherit docs
        removeAll: function() {
            var root = this.getRootNode();
            if (root) {
                root.destroy(true);
            }
            this.fireEvent('clear', this);
        },

        // inherit docs
        doSort: function(sorterFn) {
            var me = this;
            if (me.remoteSort) {
                //the load function will pick up the new sorters and request the sorted data from the proxy
                me.load();
            } else {
                me.tree.sort(sorterFn, true);
                me.fireEvent('datachanged', me);
                me.fireEvent('refresh', me);
            }
            me.fireEvent('sort', me);
        }
    }, function() {
        var proto = this.prototype;
        proto.indexSorter = new Ext.util.Sorter({
            sorterFn: proto.sortByIndex
        });
    });